Summary

Improve the out-of-box AES Crypto performance by using x86 AES
instructions when available, and by avoiding unnecessary re-expansion of
the AES key.

Motivation

AES encryption is common in applications and such applications expect
good performance. We should make it easy to get that good performance
out of the box for processors that support AES instructions in hardware.

Description

The intent of this change is to improve the out-of-the-box performance of
applications that use AES cryptography. The hotspot compiler change
(7184394) and the security library change (7185471) are actually
completely independent except for the fact that they are both related to
AES performance.

The hotspot compiler AES instruction generation happens automatically if
the x86 processor supports such instructions (there is a flag to turn
this off if desired). These instructions can be generated on either
64-bit or 32-bit x86 systems. Other CPU types are not affected.

The library change helps applications which use the same key but
re-initialize the Cipher object, switching between encrypting and
decrypting. Avoiding re-expansion of the key (7185471) changes only
private variables within the com.sun.crypto.provider.AESCrypt class.
No other classes are affected.

Testing

This change can be tested by standard benchmarks and application server
test suites, either on systems that support x86 AES instructions or on
systems that do not support x86 AES instructions to ensure there are no
unintended side effects.

Impact

Security: No impact, the changes are only improving performance

Performance/scalability: Need to verify performance of new implementation